Run `git blame` on the code pathway that's throwing the exception (in the gem.) Look at the changes that have occurred on it and either move back to a version o

Run `git blame` on the code pathway that's throwing the exception (in the gem.) Look at the changes that have occurred on it and either move back to a version of the gem that works, or change my code to suit the new version. Alternatively, look at the changelog or just manually decrement the version number until my tests pass, obviously taking care not to move back past any critical security updates. Also, the precise version numbers used in railstutorial are available in the code listings here: https://github.com/railstutorial/sample_app_2nd_ed/blob/master/Gemfile https://github.com/railstutorial/sample_app_2nd_ed/blob/mast... The (fast paced|aglie|slapdash) nature of the rails ecosystem does necessitate a certain degree of attention to detail when it comes to versioning. However this applies equally to sinatra. It's worse with node.